fMRI reveals alteration of spatial working memory networks across adolescence

Abstract

Recent studies have described neuromaturation and cognitive development across the lifespan, yet few neuroimaging studies have investigated task-related alterations in brain activity during adolescence. We used functional magnetic resonance imaging (fMRI) to examine brain response to a spatial working memory (SWM) task in 49 typically developing adolescents (25 females and 24 males; ages 12−17). No gender or age differences were found for task performance during SWM. However, age was positively associated with SWM brain response in left prefrontal and bilateral inferior posterior parietal regions. Age was negatively associated with SWM activation in bilateral superior parietal cortex. Gender was significantly associated with SWM response; females demonstrated diminished anterior cingulate activation and males demonstrated greater response in frontopolar cortex than females. Our findings indicate that the frontal and parietal neural networks involved in spatial working memory change over the adolescent age range and are further influenced by gender. These changes may represent evolving mnemonic strategies subserved by ongoing adolescent brain development.

Abstinent adolescent marijuana users show altered fMRI response during spatial working memory

“…This could be related to performance differences between task conditions, as reaction times were slower during the SWM condition than during vigilance, despite better accuracy during vigilance. This is consistent with our previous findings (Schweinsburg et al, 2005a), and suggests that the efficiency with which correct responses can be implemented may differ between task conditions. The visual discrimination necessary for the vigilance condition may be more time-consuming, and may therefore differentially recruit visual cortex between groups.…”

“…We previously characterized the relationship between age and fMRI response among 49 typically developing teens ages 12-17 using the same SWM task (Schweinsburg et al, 2005a). Younger teens evidenced increased response in superior portions of posterior parietal cortex, while older teens utilized more inferior aspects of posterior parietal cortex.…”

“…Before statistical analysis, the time series data were corrected for motion by registering each acquisition to a selected repetition with an iterated least squares algorithm (Cox and Jesmanowicz, 1999), creating an output file specifying adjustments made for three rotational and three displacement parameters for each participant. Two independent raters inspected time series data to remove any repetitions on which the algorithm did not adequately adjust for motion (Schweinsburg et al, 2005a). On average, only 5% of repetitions were removed for excessive motion; thus, on average, subjects retained 95% of repetitions, the minimum was 74%, and groups did not differ in the number of repetitions removed [F(1, 31) = 0.33, P < 0.10].…”

“…Blood-oxygen-leveldependent (BOLD) fMRI was obtained during an SWM task that typically activates bilateral prefrontal and posterior parietal networks in adolescents (Schweinsburg et al, 2005a), and has been associated with neural dysfunction among youths with alcohol use disorders (Tapert et al, 2004) as well as comorbid alcohol and marijuana use disorders (Schweinsburg et al, 2005b). We predicted that after 28 days of monitored abstinence, marijuana-using teens would demonstrate intact performance on the SWM task yet increased brain response in frontal and parietal regions.…”

The Role of Executive Control in Human Drug Addiction

“…Studies of high-risk populations (e.g., a family history of alcoholism) suggest impairments in frontal functioning are apparent prior to drug use exposure (Monti et al 2005;Schweinsburg et al 2005) and can predict later substance use (Deckel and Hesselbrock 1996; see also Ivanov et al 2008 for a review). Schweinsburg et al (2005) demonstrated that on a Go/No-go fMRI paradigm, adolescents with a positive family history of alcoholism demonstrated less inhibitory frontal response than those with no family history, despite similar task performance between groups.…”